Conotoxin peptide κ-CPTX-BTL04, preparation method therefor, and uses thereof

Abstract

Provided are a conotoxin peptide κ-CPTx-btl04 and a derivative polypeptide. The amino acid sequence of the conotoxin peptide is indicated by SEQ ID NO: 1. Also provided are a conotoxin peptide preparation method and uses of the conotoxin peptide in the treatment of diseases related to a calcium ion channel.

The invention claimed is: 
     
       1. A purified conotoxin peptide κ-CPTx-btlo 4 , which is derived from a polypeptide having the amino acid sequence of SEQ ID NO:1 by substitution of one or more amino acids therein, wherein the substitution of the one or more amino acids is selected from the group consisting of:
 (i) substitution of the serine at position 1 with threonine; 
 (ii) substitution of the leucine at position 2 with isoleucine or valine; and 
 (iii) substitution of the tryptophan at position 9 with tyrosine or phenylalanine. 
 
     
     
       2. A polynucleotide encoding the conotoxin peptide κ-CPTx-btlo 4  according to  claim 1 . 
     
     
       3. A nucleic acid construct comprising the polynucleotide of  claim 2 , and one or more control sequences operably linked thereto and being able to direct the production of the polypeptide in an expression host. 
     
     
       4. An expression vector comprising the nucleic acid construct of  claim 3 . 
     
     
       5. A transformed cell into which the nucleic acid construct of  claim 3  is transformed. 
     
     
       6. A method for inhibiting a calcium ion channel comprising administration of the conotoxin peptide κ-CPTx-btlo 4  according to  claim 1 . 
     
     
       7. A method for producing the conotoxin peptide κ-CPTx-btlo 4  according to  claim 1 , which comprises:
 (1) synthesizing the linear peptide of the conotoxin peptide κ-CPTx-btlo 4  according to its amino acid sequence by solid-phase chemical synthesis; 
 (2) performing oxidative refolding of the linear peptide obtained in step (1) with glutathione method. 
 
     
     
       8. The method according to  claim 7 , wherein the solid-phase chemical synthesis is fluorenylmethoxycarbonyl solid-phase chemical synthesis. 
     
     
       9. A transformed cell into which the expression vector of  claim 4  is transformed. 
     
     
       10. The method according to  claim 6 , wherein the calcium ion channel is a high-voltage activated calcium ion channel.